US_GEN
General - Electrical and RF safety
Electrical and RF safety groups the G0 section questions for focused review and easier weak-point tracking.
25
Questions
9
Sibling Topics
- Pool
- General
- Questions
- 25
- Topic
- Electrical and RF safety
- Region
- US
Read the condition in the stem before comparing key terms in the options.
Study rules, calculations, and equipment questions as separate patterns.
After this topic, return to the full pool for mixed practice.
Topic Study Guide
This topic covers Electrical and RF safety (G0) for the FCC General exam, focusing on RF exposure evaluation, duty cycle calculations, safe wiring practices (AWG), and tower/generator safety protocols.
High-Yield Checks
- RF exposure evaluation methods: Know that OET Bulletin 65, computer modeling, and calibrated field strength meters are all acceptable compliance methods.
- Duty cycle and time averaging: A lower duty cycle permits higher transmit power; time averaging refers to specific periods, not a 24-hour cycle.
- AWG wire sizes and breakers: Memorize that AWG 12 pairs with 20A, AWG 14 with 15A, and fuses are only placed on hot wires.
- Tower and equipment safety: Power must be locked out and tagged before climbing, and lightning grounds must be located outside the building.
Trap Patterns
- Confusing RF radiation with ionizing radiation by assuming it causes 'radiation poisoning'; it actually heats body tissue.
- Blindly selecting 'All these choices are correct.' For example, holding a tower with one hand is unsafe, and FCC rules do not mandate neighbor notifications.
- Misunderstanding the AWG system by assuming larger numbers mean thicker wires. Smaller AWG numbers indicate thicker wires with higher current capacity.
- Assuming an SWR meter can measure spatial field strength; a calibrated field strength meter with a calibrated antenna is actually required.
Review Steps
- Review RF exposure rules, focusing on the mathematical relationship between duty cycle, time averaging, and Maximum Permissible Exposure (MPE).
- Memorize common AWG wire sizes versus breaker ratings, and clarify the distinct roles of hot, neutral, and ground wires in circuit protection.
- Learn how GFCIs work, specifically that they detect hot-to-ground leakage rather than overvoltage or overcurrent.
- Summarize safety protocols for tower work, generator operation, and handling lead-tin solder to eliminate common-sense misconceptions.
Quick Checks
- What is the minimum AWG wire size for a 20-ampere circuit breaker?
- What action must be taken if an RF evaluation shows exposure exceeds permissible limits?
- Under what specific condition will a GFCI disconnect AC power?
- What is the primary physical effect of RF energy on human body tissue?
Questions in This Topic
Choose Practice ModeG0A01What is one way that RF energy can affect human body tissue?G0A02Which of the following is used to determine RF exposure from a transmitted signal?G0A03How can you determine that your station complies with FCC RF exposure regulations?G0A04What does “time averaging” mean when evaluating RF radiation exposure?G0A05What must you do if an evaluation of your station shows that the RF energy radiated by your station exceeds permissible limits for possible human absorption?G0A06What must you do if your station fails to meet the FCC RF exposure exemption criteria?G0A07What is the effect of modulation duty cycle on RF exposure?G0A08Which of the following steps must an amateur operator take to ensure compliance with RF safety regulations?G0A09What type of instrument can be used to accurately measure an RF field strength?G0A10What should be done if evaluation shows that a neighbor might experience more than the allowable limit of RF exposure from the main lobe of a directional antenna?G0A11What precaution should be taken if you install an indoor transmitting antenna?G0A12What stations are subject to the FCC rules on RF exposure?G0B01Which wire or wires in a four-conductor 240 VAC circuit should be attached to fuses or circuit breakers?G0B02According to the National Electrical Code, what is the minimum wire size that may be used safely for wiring with a 20-ampere circuit breaker?G0B03Which size of fuse or circuit breaker would be appropriate to use with a circuit that uses AWG number 14 wiring?G0B04Where should the station’s lightning protection ground system be located?G0B05Which of the following conditions will cause a ground fault circuit interrupter (GFCI) to disconnect AC power?G0B06Which of the following is covered by the National Electrical Code?G0B07Which of these choices should be observed when climbing a tower using a safety harness?G0B08What should be done before climbing a tower that supports electrically powered devices?G0B09Which of the following is true of an emergency generator installation?G0B10Which of the following is a danger from lead-tin solder?G0B11Which of the following is required for lightning protection ground rods?G0B12What is the purpose of a power supply interlock?G0B13Where should lightning arrestors be located?